Cutter mounting



NOV. 30, 1937. Q EFROMSON 2,100,640

CUTTER MOUNTING Filed Feb. 25, 1937 His/60* Patented Nov. 30,1937

2,100,640 CUTTER MOUNTING Philip C. Efromson, Los Angeles County, Calif., assignor to Globe Oil Tools Company, Los Nietos, Calif., a corporation of California Application February 23, 1937, SerialNo. 126,987

15 Claims.

This invention relates to well drilling tools and relates more particularly to anti-friction bearings or mountings for the cutters of rotary well drilling tools. A general 'object of this invention is to provide practical, improved and long wearing cutter mountings. 4

Another object of this invention is to provide cutter mountings for adjacent roller cutters of a well bit in which each cutter and its bearing elements are assembled as a unit to facilitate the manufacture and the assemblage of the same.

Another object of this invention is to provide ball bearing cutter mountings each embodying a plurality of rows of balls and each having at least one row of balls operating to definitely position its cutter and to take the end thrusts in both directions as well as the radial thrusts.

Another object of this invention is to provide cutter mountings of the character mentioned in which each row of balls may assume end thrusts in at least one direction as well as assume the radial thrusts from the cutter.

Another object of this invention is to provide cutter mountings of the character mentioned in which the races or grooves receiving the balls that transmit end thrusts in both directions are deep and present large surfaces for contact by the balls and, therefore, are long wearing.

,Another object of this invention is to provide cutter mountings of the character mentioned embodying novel interfltting parts for preventing rotation of the race elements and for definitely positioning the elements.

A further object of this invention is to provide anti-friction cutter mountings of the character mentioned that may be easily and quickly assembled with the assurance that the parts are properly positioned.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is a side elevation of a bit embodying the present invention with the lower portion broken away to illustrate the cutter mountings and cutters in vertical cross section. Fig. 2 is an enlarged plan elevation of the assembly of a washer, a race member, and a race projection removed from the bit and Figs. 3 and 4 are transverse sectional views taken as indicated by lines 3-3 and 44,-respeciively, on Fig. 2. .The cutter mounting means of vention may be embodied in'well drilling tools of the present invarious characters. In the following detailed description I will describe one form of the invention as embodied in a rotary rock bit having two diametrically opposite sets of inner roller cutters. It is to be understood that the invention is not to 5 be construed as limited or restricted to the specific form or application about to be described.

The rotary rock bit illustrated in the drawing includes a shank or body In adapted to be connected with the lower end of a rotary well drilling string. The body ID has a threaded pin H or its equivalent for connecting with the lower end of the drilling string. Two diametrically opposite legs 12 project downwardly from the lower end of the body Ill. The legs l2 have fiat substantially 15 vertical bearing faces l3 on their inner sides. The lower ends I4 of the legs l2 may be flat and substantially horizontal and the lower outer corners of the legs may be bevelled oil as illustrated. A substantially vertical web l5 projects downwardly from the lower end of the bit body Ill. The lower endof the web I5 is some distance above the plane of the lower endsit of the legs l2 and is preferably fiat and horizontal. Suitable ports 16 are provided in the lower end of the body Hi to discharge the circulation fluid downwardly against the cutters.

The present invention includes, generally, the combination of two like sets of roller cutters A and B and means for rotatably mounting the cutters A and B-comprising a central support I! on the V body web l5, pins l8 carried by the legs I2 and a the support l1 and ball and race means l9 rotatably supporting the cutters A and B on the pins '8- The cutters A and B are provided insets, each set being carried by a pin l8 through the medium of the ball and race means Hi to be subsequently described. In the form of the lnventionillustrated each set of cutters includes a cutter A and a 40 cutter B. The cutters A and B are roller cutters and the cutters of each set are alike. The cutters A are substantially cylindrical and are located adjacent the central vertical axis of the bit to act I on the central portion of the well. Peripheral cutting teeth 20 are provided on the cutters A. In the case illustrated the teeth 20 are axial and are notched. The opposite ends of the inner cutters A are preferably fiat as illustrated. Each cutter A has a central longitudinal opening 2|. The

cutters B are frusto-conical having pitched or -tapered peripheries. The cutters B are arranged with their small ends facing inwardly toward the central axis of the bit. In the preferred construction the cutters B are larger than the cutters A,

web IE to carry the inner ends of the pins l8.

. The support I1 is a block-like member and constitutes a race element of the means l9 as will be subsequently described. The support bears upwardly against the web l5 having a flat upper end engaging against the flat lower end of the web. A cap screw 24 is arranged through an opening 25 in the web I5 and is threaded in an opening 26 in the support I1 to secure the supportto the web. The opposite sides of the support I! are preferably inclined downwardly and inwardly toward the central axis of the bit. Cylindrical bosses 2.! project from the opposite sides of the support l1. Tubular extensions or race projections 28 extend outwardly from the bosses 21 toward the legs l2. The race projections 28 are integral with the support I1 and constitute bushings or bearing shafts for the inner cutters A as will be hereinafter described. The bosses 21 and the race projections 23 extend into the openings 2| of the cutters A and are inclined downwardly and outwardly relative to the vertical axis of the bit body In. The race projections 28 are of sufficient length to project outwardly to or beyond the outer ends ofthe cutters A. The projections 28 have cylindrical peripheries and extend through the cutter openings 2| with suitable clearance.

The pins |8 extend between the legs l2 and the support I! to tie the legs to the support, to carry the cutters B and their bearing means, and to assist in supporting the projections 28 and the cutters A carried thereby through the means l9. The pins 8 are in the nature of screws or bolts passed inwardly through openings 29 in the legs |2 and threaded into the inner portions of the openings 38 in the tubular projections 28. Heads 3| are provided on the outer ends of the pins |8 and'are received in sockets 32 in the outer sides of the body legs I2. Portions 33 of the pin heads 3| are peened into notches 34 in the outer sides of the legs l2 to lock the pins I8 against turning and unthreading. The longitudinal axes of the pins |8 are inclined downwardly and outwardly with respect to the vertical axis of the bit. The pins l8, of course, extend through the cutters A and their mountings.

The ball and race means l9 for rotatably supporting or mounting the pairs of cutters A and B may be identical and I will proceed with a detailed description of one means |9 for supporting one pair of cutters A and B, it being understood that this description is equally applicable to the other means IS.

The ball and race means l9 includes the above described race projections 28 extending into the cutters A from their inner ends. A plurality of sets or rows of balls rotatably supports the cutter A on its respective race projection 28. In the simple form of the invention illustrated two spaced rows of balls 35 and 36 rotatably support the cutter A on it's race projection 28. The annular series of balls 35 cooperates with an annular groove 31 in theprojection 28 anda race or groove 38 on the wall of the cutter opening 2|. The groove 31 is provided in the corner occurring between the boss 21 and the projection 28 and is preferably comparatively deep to extend into the body of the projection 28 proper. The inner radially toward the axis of rotation of the cutter A and inwardly toward the central vertical axis of the bit. The grooves 31 and 38 are partially circular in transverse cross section to properly receive the spherical balls 35. It will be noted that the race groove 38 facing inwardly and radially provides for the transmission of inward end thrusts from the cutter A through the balls 35 as well as the radial thrusts from the cutter.

The balls 36 cooperate with an annular groove 39 in the outer portion of the race projection 28 and an annular race or groove 4|) in the wall of the cutter opening 2| The groove 39 is adjacent the outer end of the projection 28 and is of substantial depth to receive substantial portions of the balls 36. The groove 40 is likewise of substantial depth to receive substantial portions of the balls 36 and directly radially opposes the groove 39. The grooves 39 and 40 are partially circular in transverse cross section to properly receive the balls 36. The grooves 39 and 40 shaped and related as just described receive the balls 36 for the transmission of end thrusts from the cutter in both directions, as well as the radial thrusts from the cutter. The balls 36 cooperating with the grooves 39 and 40 definitely locate or position the cutter A.

It is believed that it will be understood how the annular series of balls 35 may be readily arranged in the groove 31 when the cutter A is slid into position over the race projection 28. The enlarged inner portion of the cutter opening 2| permits the easy assembly of the balls 35 in the grooves 31 and 38. The invention provides novel means for facilitating the arrangement of the balls 36 in the grooves 39 and 40. In accordance with the invention a slot or notch 4| is provided in the outer end of the race projection 28. The notch 4| is fiat sided and extends inwardly to or beyond the groove 39. The notch 4| is provided to permit the easy insertion of the balls 36 in the grooves 39 and 48. The balls 36 may be easily inserted through the notch 4| until the registering grooves 39 and 40 are full, whereupon a part on the" bushing or race element of the cutterB is inserted in the notch 4| to prevent the loss of the balls 36. This part or element for occupying the notch 4| will be subsequently described.

The means l9 includes a bushing or race 43 on the pin l8 for extending through the cutter B. The race 43 is a tubular element arranged on the pin |8 to have its inner end in'cooperation with the outer end of the race projection 28. The inner portion of the race 43 may be of the same diameter as the projection 28. The outer portion 43 of the race 43 is enlarged in diameter and is received in an enlarged outer portion of the cutter opening 23. The race 43 extends through the cutter opening 23 with substantial clearance. The outer end of the race 43 is adjacent or slightly inward of the outer end of the cutter B. A washer 44 is arranged on the pin 8 between the oute end of the race 43 and the bearing surface I3 of the leg |2. The Washer 44 holds the race 43 against endwise movement. The washer 44 may be partially received in the cutter opening 23 but is not engaged by the cutter. A lug 45 is provided on the lower end of the washer 44 .and may be welded to the lower end l4 ofthe leg |2 at 46. The welding 46 definitely holds the washer 44 against rotation and prevents chattering of the washer and the other bearing parts. A tongue 41 projects axially from the inner end of'the race 43 and fits the above-described notch 4|. The tongue 41 is the element mentioned above which prevents the loss of the balls 36 from the grooves 39 and 48. A groove 48 is provided in the outer side of the tongue 41 and registers with the groove 39 to complete the groove so that it'properly receives the balls 36. The tongue 41 fitting the notch 4| retains the balls 46 in place and =prevents relative turning between the race 43 and the race projection 28. I

The means I 9 includes a plurality of spaced series of balls 58, 5| and 52 cooperating with the interior of the cutter B and with the race 43 to rotatably support the cutter on .the race. The

.balls 58 are within the inner portion of the cutter race 43 and an annular shoulder 54 on the wall of the cutter opening 23. The groove 53 is of sufficient depth to receive substantial portions of the balls 58. The shoulder 54 is concaved and shaped to partially receive the balls 58. In accordance with the invention the shoulder 54 faces radially inward toward the axis of rotation of the cutter B and outwardly toward the outer end of the cutter and is related to the groove 53 so that the balls 58 assume the outward end thrusts on the cutter B as well as the radial thrusts on the cutter. The portion of the cutter opening 23 extending outwardly from the shoulder 54 is sufliciently large in diameter to allow.

the outward end thrusts from the cutter-to the race 43.

The balls 5| which are somewhat larger than the balls 58 cooperate with an annular groove 55 in the race 43 and a shoulder 56 on the wall of the cutter opening 23. The groove 55 occurs in the corner between the body. of the race 43 and the enlarged race portion 43 and is suificiently deep to extend radially into the body of the race proper. The shoulder 56 occurs at the inner end of the enlarged outer portion of the opening 23 and faces inwardly toward the axis of rotation of the cutter B and outwardly toward the outer end of the cutter. The shoulder 56, of

to bring the shoulder 56 in engagement with the balls 5| when the parts are being assembled.

The balls 52 cooperate with an annular groove 51 in the enlarged outer end portion 43 of the race 43 and an annular groove 58 in the wall The portion of the cutter opening of the cutter opening 23. The grooves 51 and 58 are directly opposite one another and are adjacent the outer end of the cutter B. Both grooves 51 and 58 are 9f substantial depth to rev ;.:eive substantial portions of the balls 52. With the above described formation of the grooves 51 and 58 the balls 52 are operable to transmit end thrusts in both directions from the cutter B to the race 43 as well as transmit the radial thrusts from the cutter to the race. The balls 52 cooperating with the grooves 51 and 58 also definitely position the cutter B on the race 43.

A longitudinal notch 68 is provided in the outer end portion 43' of the race 43 and extends inwardly beyond the groove 51. The notch 68 is provided to facilitate the insertion of the balls 52 in the grooves 51 and 58. When the grooves 51 and 58 are fully occupied by the series of balls 52 a tongue 6| on the washer 44 is inserted in the notch 68 to prevent the displacement of the balls. A suitably shaped groove 62 is provided in the outer surface of the tongue 6| toregister with the groove 51 so that the groove 51 in efiect constitutes a continuous or annular groove to properly carry the balls 52. It will be observed that the cutter B'is rotatably supported by the longitudinally spaced series of balls 58, 5| and 52. The balls 58 and 5| are operable to transmit the outward end thrusts from the cutter B to the race 43 as well as the radial thrusts. The series of balls 52 cooperating with the grooves 51 and 58 are operable to transmit both the inward and outward end thrusts from the cutter B to the race 43 of the radial thrusts on the outer portion of the cutter.

To assemble one set of cutters A and B and its bearing means l9 the balls 35 are first arranged in the groove 31 and the cutter A and the race projection 28 are moved relative to one another to bring the grooves 31 and 38 in proper cooperation with the balls. The balls 36 are then inserted through the notch 4| to occupy the registering grooves 39 and 48. The notch 4| is such that the balls 36 may be easily inserted into the registering grooves 39 and 48. The balls 58 are then arranged in the groove 53 and the balls 5| are arranged in the groove 55. The balls 58 and 5| are arranged in place before the groove 53 is moved inwardly past the shoulder 56. When the balls 58 and 5| are properly, positioned the race 43 is moved into the cutter B to bring the balls 58 in proper contact with the shoulder 54 and to bring the balls 5| in proper cooperation with the shoulder 56. This brings the tongue 41 in position for insertion in the notch 4|. The pin I8 is not in place and the assembly of the cutter B and the race 43 may be moved laterally relative to the cutter A andthe race projection 28 so that the tongue 41 is first received in the opening 38 and is then moved outwardly into the notch 4| to its final position. The tongue 41 is adapted to completely occupy the notch 4| and itsgroove 48 registers with the groove 39 to properly cooperate with the balls 36. The balls 52 are then inserted in the registering grooves 51 and 58 through the notch 68. When the balls 52 have been properly positioned the washer 44 is arranged in place so that its, tongue 6| occupies 4 respective mountings may be simultaneously assembled on the bit body III.

In the operation of the tool the cutters A and B act on the bottom wall of the well bore and their engagement with the earth formation results in their independent rotation. The cutters A and B are supported for free independent rotation by the anti-friction ball bearing means. The cutter A is supported by the spaced series of balls 35 and 36, the balls 38 assuming radial thrusts and end thrusts in both directions and the balls 35 assuming radial thrusts and inward end thrusts. The longitudinally spaced series of balls 35 and 36 dependably support the cutter A for free rotation. The three longitudinally spaced series of balls 50, 5| and 52 rotatablysupport the cutters B. The balls 50 and 5| as-. sume radial thrusts and outward end thrusts while the balls 52 assume radial thrusts and end thrusts in both directions. The cutters A and B are both entirely supported by spaced sets of ball bearings and thrust washers or the like are not required. The grooves 31, 39, 40, 53, 55, 51 and 58 are deep and present extensive surfaces for contact by the cutter supporting balls and, therefore, are very long wearing. The ball engaging shoulders and grooves on the interiors of the cutters A and B have relatively large circumferences and, therefore, are long wearing. The tongues 41 serve to dependably retain the balls 36 in their grooves 39 and 40 and the tongues 6i occupy the notches 60 to prevent the loss of the balls 52. The cutters A are definitely positioned by the balls 36 cooperating with the deep grooves 39 and and the cutters B are definitely positioned by the balls 52 cooperating with the deep grooves 51 and 5B. The cutter mounting means of the present lnvention is dependable and long Wearing and supports the cutters for free rotation.

Having described only a typical preferred form and application of my invention I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. A cutter assembly for a well drill comprising, a support, adjacent cutters surrounding the support, a race member on the support and within one cutter, the race member and said cutter having opposing annular grooves, balls in the grooves, a race member on the support within other cutter, and a part on the second mentioned race member preventing displacement of said balls.

2. A cutter assembly for a well drill comprising, a support, adjacent cutters surrounding the support, a race member on the support and within one cutter, the race member and said cutter having opposing annular grooves, the race member having an opening communicating with the groove in the member, balls inserted into the grooves through said opening, a race member on the support and within the other cutter, and a part on the second mentioned member extending into said opening to prevent the escape of the balls.

3. A cutter assembly for a well drill compris ing, a support, adjacent cutters surrounding the support, a race member on the support and within one cutter, the race member and said cutter having opposing annular grooves, the race member having an opening communicating with the groove in the member, balls inserted into the grooves through said opening, a race member on the support and within the other cutter, and an axially projecting tongue on the second mentioned member occupying said opening to prevent the escape of the balls.

4. A cutter assembly for a well drill comprising, a support, adjacent cutters surrounding the support, a race member on the support and Within one cutter, the race member and said cutter having opposing annular grooves, the race member having an opening communicating with the groove in the member, balls inserted into the grooves through said opening, a race member on the support and within the other cutter, and a part on the second mentioned a support carried by the body, a rotatable cut-' ter surrounding the support, a race member on the support within the cutter, and a plurality of spaced series of balls rotatably supporting the cutter on the race member, one series of balls transmitting end thrusts in both directions from the cutter to the member, and at least one series of balls transmitting end thrusts in one direction from the cutter to the member.

'7. A rotary well drilling bit comprising, a body, a support carried by the body, a rotatable cutter surrounding the support, a race member on the support Within the cutter, axially spaced pairs of opposing annular race surfaces on the member and the interior of the cutter, and balls cooperating with the opposing surfaces to rotatably support the cutter, the surfaces of one of said pairs being depressed below the adjacent surfaces of the member and cutter whereby the balls cooperating therewith are operable to transmit end thrusts in both directions.

8. A rotary well drilling bit comprising, a body, a support carried by the body, a rotatable cutter surrounding the support, a race member on the support within the cutter, axially spaced pairs of opposing annular race surfaces on the member and the interior of the cutter, and balls cooperating with the opposing surfaces to rotatably support the cutter, the surfaces of one of said pairs being depressed below the adjacent surfaces of the member and cutter whereby the ballscooperating therewith are operable to transmit end thrusts in both directions, the surfaces of at least one of said pairs being related so that the balls cooperating therewith are operable to transmit end thrusts in one direction.

9. A rotary Well drilling tool including a body, a support carried by the body, rotatable cutters around the support, race members on the support within the cutters, one race member and the interior of the surrounding cutter having opposing annular grooves, and said race member having an opening communicating with its groove, balls in the grooves rotatably supporting the cutter, the balls being inserted through said opening, the grooves being of such depth that thebaIIs transmit axial thrusts in both direcan opening communicating with its groove of said pair through which the balls are inserted in the said pair of grooves, and a tongue on the adjacent race member extending into said open-' ing to prevent theloss of the said balls.

11. A rotary well drilling bit comprising, a body, a support carried by the body, a rotatable cutter surrounding the support, a race member on the support within the cutter, there being opposing annular grooves in the member and the interior of the cutter, the member having an opening extending from one end to its groove, balls inserted through said opening into the grooves to rotatably support the cutter, a washer on the support between said end of the member and an adjacent surface of the body, and a part on the washer extending into said opening to prevent the loss of the balls therethrough.

12. A rotary well drilling bit comprising, a

body, a support carried by the body, a rotatable cutter surrounding the support, a race member on the support within the cutter, there being opposing annular grooves in the member and the interior of the cutter, the member having an opening extending from one end to its groove, balls inserted through said opening into the grooves to rotatably support the cutter, a washer rigidly attached to the body, and a part on the washer occupying said opening.

13. A rotary well drilling bit comprising, a body, a support carried by the body, a rotatable cutter surrounding the support, a race member on the support within the cutter, there being opposing annular grooves in the member and the interior, of the cutter, the member having an opening extending from one end to its groove,

balls inserted through saidv opening into the grooves to rotatably support the cutter, a washer rigidly attached to the body, and a part on the washer occupying said opening and having a groove registering with and completing the groove in said member.

14. A rotary well drilling bit comprising, a body, a support carried by the body, a rotatable cutter surrounding the support, a race member on the support within the cutter, and a plurality of spaced series of balls rotatably supporting the cutter on the race member, one series'of balls transmitting axial thrusts in both directions, the other series of balls each transmitting axial thrusts in one direction.

15. A rotary well drilling tool including, a body, a support carried by the body, rotatable cutters around the support, racemembers on the support within thecutters, the race members posing ball grooves, balls in said grooves rotatably and cutters having axially spaced pairs of opsupporting the cutters, one pair of grooves in grooves, a part projecting from one member and occupying the said opening in the other member, and an element secured to the body and having a part occupying the said opening in the first mentioned member.

' PHILIP C. EFROMSON;

each cutter and member assembly being of such 3 I 

